Fabrication of novel strontium-coated bioactive ceramic-glass (C2S(2P6)C2S) 3D-porous scaffold for the proliferation and osteogenic differentiation of bone marrow-derived mesenchymal stem cells

This study fabricated novel multilayer 3D-scaffolds by coating bioactive Calcium silicate (Ca2SiO4)/glass phase (calcium ultraphosphate, Ca2P6O17)/Ca2SiO4 (C2S(2P6)C2S) 3D scaffolds with strontium (Sr) for osteogenic differentiation of bone marrow-derived mesenchymal stem cells (MSCs). Hence, for the first time, C2S(2P6)C2S/Sr 3D-scaffolds were fabricated by sol-gel method and their characterization (X-Ray diffraction analysis (XRD), scanning electron microscopy (SEM) and Mercury Porosimetry), effect in MSCs proliferation (cytotoxicity and mRNA expression) and osteogenic differentiation (staining and mRNA expression) were evaluated. The porosity and SEM data showed that the porosity (31.66% for C2S(2P6)C2S and 32.14% for C2S(2P6)C2S/Sr), pore size (<300 μm) and microstructure were not altered between C2S(2P6)C2S and C2S(2P6)C2S/Sr 3D-scaffolds, respectively. MSCs proliferation rate was increased by C2S(2P6)C2S/Sr 3D-scaffold via upregulating c-Fos and TGF-β1 mRNA expression. Alizarin Red (calcium), von-kossa (calcium-phosphate) and alkaline phosphatase (ALP) staining were higher in differentiated MSCs cultured on C2S(2P6)C2S/Sr 3D scaffold than in control. The osteogenic stimulatory effect of C2S(2P6)C2S/Sr 3D scaffold could be justified by increasing osteogenic stimulatory genes such as collagen type-I, Runx2, osteocalcin and ALP expression in differentiated MSCs. Further, SEM images proved that the C2S(2P6)C2S/Sr 3D scaffold-cultured cells had unique morphology similar to biological tissues. Accordingly, this is the first report evidencing the MSC proliferative and osteogenic stimulatory ability of strontium-coated C2S(2P6)C2S 3D-scaffold, which greatly impacts future strategic therapies in dentistry and bone regeneration.